Chris Teoh (left) weds Ivan Hinton. Their wedding might be in doubt later this week when the High Court rules on the issue. Photo: AP

Australia's first gay marriages were celebrated yesterday in the national capital, Canberra, despite a possible court ruling against them later this week.

Stephen Dawson, a member of the Western Australian parliament, was the first to get married, with a midnight wedding on the lawns of the federal parliament, the Australian Broadcasting Corporation reported.

"This is about us professing our love for each other and reminding each other after 10 years that we still love each other and at least for the moment our relationship will be legally recognised as a marriage," he said after marrying partner Dennis Liddelow.

The Australian Capital Territory (ACT) passed legislation in October which made it the only jurisdiction in the country to permit gay marriage, and more than 20 couples were set to wed there yesterday, the earliest opportunity to do so.

"This is an important day for same-sex couples and our families, but also for the nation, because today Australia is a fairer and more equal country that values love more highly," Australian Marriage Equality's Rodney Croome said.

The Australian Capital Territory, home to the city of Canberra and the national parliament, pressed ahead with its legislation despite warnings it was inconsistent with federal laws that do not permit same-sex weddings. Australia's Marriage Act defines marriage as between a man and a woman, so while same-sex civil unions are available in a majority of Australian states these couples are not formally recognised as married by the government.

The federal government is therefore challenging the validity of the Australian Capital Territory legislation in the High Court and a ruling is due on Thursday.

The ACT government has said it is confident its law is strong enough to prevail but has admitted the legal challenge could have implications for those couples who choose to wed.

"Regardless of what happens in the High Court, the significance of this moment will remain and send a strong signal about what a contemporary 21st century Australia should look like," ACT Attorney General Simon Corbell said.

Gay marriage has recently been a high-profile political issue in Australia, home to one of the world's largest annual gay and lesbian Mardi Gras celebrations in Sydney.

Federal parliament last year voted down laws allowing same-sex marriage when conservative members opposed the move after leader Tony Abbott denied them a conscience vote on the sensitive issue.

The Australian Christian Lobby group also spoke against gay marriages yesterday, warning they would have "big social consequences".

"We hear about equal love all the time but we don't hear about what it means for children," spokesman Lyle Shelton told Sky News.

This article appeared in the South China Morning Post print edition as Court ruling hangs over same-sex weddings